Adjustable Height Standing Desk

ABSTRACT

A height adjustable, standing desk suitable for use on conventional desks is presented. The standing desk of the present invention utilizes a scissor lift mechanism to raise and lower the desktop surface. The standing desk is presented in two embodiments, one of which uses a motor drive assembly to raise and lower the desktop and one of which uses is manually raised and lowered and features a biasing spring and height locking arrangement. Slide out and clip on keyboard assemblies are also presented.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to ergonomic workplace environments and more particularly to an adjustable height standing desk that allows a user to work while standing up.

Background of the Invention

Sitting for long periods of time such as during a typical work day has long been associated with decreased wellbeing and overall quality of health. Taking regular breaks from sitting during the workday may have several positive outcomes. For example, standing for periods of time during the workday may provide a worker with more energy and may increase alertness. Standing for periods of time during the work day may also reduce weight and generally increase a worker's overall health.

Despite the known benefits of standing during the workday few office workers are able to stand for significant periods of time because the majority of office and cubical spaces are equipped with conventional height desks that are only suitable for office work when a worker is in a sitting position. Company rules generally prevent workers from removing or replacing their employer supplied desks. Therefore, there exists a need in the art for a portable “high” desk that sits on top of a conventional desk. Ideally, such a desk will have an adjustable height range to accommodate workers of varying heights and preferences. Such a desk will allow workers to gain the health and wellbeing benefits available by standing for periods of time during the workday.

SUMMARY OF THE INVENTION

The present invention provides an adjustable height, standing desk for use on top of a conventional desk that allows office workers to work while standing during the work day and thereby gain the advantages of breaks from continual sitting for hours at a time. The standing desk of the present invention is readily portable between locations and is designed to allow for the ready replacement and/or repair of component parts, if needed, to enhance serviceability. In general, the standing desk includes a base frame assembly, an intermediate frame assembly and an upper frame assembly, where the upper frame assembly is equipped with a top support surface designed to support typical desktop materials, i.e. books, writing pads, keyboards, display monitors and like materials. The base and intermediate frame assemblies may optionally be equipped with similar base and intermediate support surfaces which may also be used to support desktop materials when the adjustable height, standing desk is in a raised position.

The base, intermediate and upper frame assemblies are generally planar assemblies which are interconnected by opposing scissor lift linkage assemblies which raise and lower the intermediate and upper frame assemblies in relation to the base assembly and maintain the assemblies in a generally parallel relationship relative to each other as the top support surface of the standing desk moves between raised and lowered positions.

In the exemplary embodiment of the standing desk depicted in the figures, the base, intermediate and upper frame assemblies are of generally rectangular configuration having short sides and longs sides with the scissor lift linkage assemblies being installed in the opposing short sides. The scissor lift linkage assemblies on the opposing sides are identical, therefore only one linkage assembly need be described in detail.

The exemplary scissor lift linkage assembly of the standing desk of the present invention, comprises a pair of interconnected lower and upper links, where each pair of links, i.e. upper and lower, is pivotally connected at mid-length. Each link of the upper and lower link pairs has an upper end and a lower end. The lower ends of the lower link pair are pivotally connected to a rail of the base frame assembly. One of the pivotal connections is a fixed connection where the lower end of the link is pinned to the rail, referred to as the base frame fixed pivot connection, and the other is a movable connection where the lower end of the link is connected to a roller that travels within the rail of the base frame assembly, referred to as the base frame movable pivot connection. The provision of a roller significantly reduces the frictional surface contact between the link and the rail of the base frame assembly.

The upper ends of the lower link pair are pivotally connected to lower ends of the upper link pair. One of the upper and lower link pivot connections is fixed to a rail of the intermediate frame assembly, referred to as the intermediate frame fixed pivot connection, and the other pair of upper and lower link connections is connected to a roller which is slidable within the rail in the intermediate frame assembly, referred to as the intermediate frame movable pivot connection.

Similarly, the upper ends of the upper link pair are pivotally connected to a rail of the upper frame assembly. One of the pivot connections is a fixed connection pinned to the rail of the upper frame assembly, referred to the as the upper frame fixed pivot connection, and other pivot connection is connected to roller which slides within the rail of the upper frame assembly, referred to as the upper frame movable pivot connection.

It should be noted that all of the fixed pivot connections are all vertically aligned, i.e. the base frame fixed pivot connection, the intermediate frame fixed pivot and upper frame fixed pivot connection are vertically aligned with each other. The horizontal position of the base, intermediate and upper frame fixed pivot connections does not change as the scissor linkages are used to raise and lower the top support surface. The movable pivots are also vertically aligned with each other, i.e. the base frame movable pivot connection, the intermediate frame movable pivot and upper frame movable pivot connections are vertically aligned with each other. The movable pivot connections however, move (slide) horizontally along the frame rails as the scissor linkages are used to raise and lower the top support surface. During horizontal movement of the base, intermediate and upper frame movable pivot connections, the movable pivot connections remain vertically aligned.

In one embodiment of the standing desk of the present invention, referred to as the “power” version, the scissor lift linkage assemblies are electrically operated. The drive mechanism for raising and lowering the linkage assemblies features ball screw assemblies which are located within the base frame assembly. One of the ball screw assemblies is disposed adjacent and parallel to one of short sides of the base frame assembly and the other of the ball screw assemblies is disposed adjacent and parallel to the opposite short side of the base frame assembly. One of the ball screw assemblies is motor driven by an electric motor. The two ball screw assemblies are synchronized via a chain and gear connection between the two screws.

As is known in the art, ball screw assemblies comprise a screw portion and a nut portion where the nut moves linearly along the length of the rotating screw. Typically clockwise rotation drives the nut forward along the length of the screw and counter-clockwise rotation drives the nut backwards. In the standing desk of the present invention, the nut of each ball screw assembly is connected to one of the opposing scissor lift linkage assemblies. The nuts of the ball screw assemblies are connected to their respective linkage assemblies via a drive arm.

Referring to one of the scissor lift linkage assemblies only, by way of example, each of the opposing linkages being the same, the drive arm is connected to the link of the lower link pair which has its lower end connected to the base frame movable pivot connection (i.e. the roller). The drive arm is rigidly fixed to the lower link, but is pivotally connected to the ball screw assembly nut. The ball screw assembly itself is pivotally mounted to the base frame assembly at one end and is free to move at the other end. Thus, as the screw of the ball screw assembly rotates clockwise (electric motor driven), the nut moves forwardly along the screw shaft while the ball screw assembly itself rotates upwardly as the scissor lift linkage assembly raises the top surface upwardly. Likewise, when the screw of the ball screw assembly is rotated counterclockwise, the nut moves backwardly along the screw shaft while the ball screw assembly itself rotates downwardly as the scissor lift linkage assembly lowers the top surface. As referenced above, both of the ball screw assemblies move in tandem because the assemblies are synchronized via the chain and gear assembly.

In another embodiment of the standing desk of the present invention, referred to as the “manual version,” power apparatus is not used to operate the scissor lift linkage assemblies. Rather, the manual version is equipped with biasing springs between the upper ends of the upper linkage pairs which bias the scissor lift linkage assemblies in a fully raised position. If less than the full height of the standing desk is desired, manual force exerted by a user is used to lower the top surface of the standing desk and a user actuated lock assembly is provided to lock the desk at the desired height. Release of the lock assembly returns the desk to its full extended height. A feature of the design is that the tensions springs are located such that they have an “over-center” position such that compression of the height of the desk to below an over-center height causes the tension springs to hold the standing deck in the fully lowered position.

In other embodiments, the standing desk of the present invention may be equipped with either slide out or clip-on keyboard trays for use with computers, word processors and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of an embodiment of the standing desk of the present invention which incorporates a power lifting apparatus, shown in a raised position and showing an optional slide-out keyboard tray.

FIG. 2 is a schematic perspective view of the embodiment of standing desk of FIG. 1, with the frame covers and keyboard tray removed.

FIG. 3 is a schematic top view of standing desk of FIG. 2, showing a linkage drive assembly.

FIG. 4 is a schematic sectional side view showing a scissor lift linkage assembly of the standing desk of FIG. 3.

FIG. 5 is a schematic perspective view of an optional slide out keyboard tray suitable for use with the standing desk of the present invention.

FIG. 6 is a partially exploded schematic perspective view of an alternative embodiment of the standing desk of the present invention, referred to as the manual version, shown in a raised position, with an optional clip on keyboard tray and the top cover shown separated from the upper frame to show additional details of the invention.

FIG. 7 is a schematic sectional side view of the standing desk of FIG. 6 showing the scissor lift linkage assembly.

FIG. 8 is a schematic top view of the standing desk of FIG. 6 showing the arrangement of the biasing springs and height adjustment components.

FIG. 9 is a partial, schematic perspective, top view of the standing desk of FIG. 6 showing the arrangement of the biasing springs and certain height adjustment components.

FIG. 10 is a partial section schematic view taken along the line 10-10 of FIG. 9, showing the roller and retractable pin locking feature of the invention.

FIG. 11 is a perspective view of an optional clip-on keyboard tray suitable for use with the standing desk of the present invention.

FIG. 12 is a partial section schematic view taken along the line 12-12 of FIG. 4, showing a roller connected to a lower link of the linkage assembly of the invention.

FIG. 13 is a partial section schematic view taken along the line 13-13 of FIG. 4, showing a roller connected to a lower and upper link of the linkage assembly of the invention.

FIG. 14 is a partial section schematic view taken along the line 1444 of FIG. 4, showing a roller connected to an upper link of the linkage assembly of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The invention may, however, may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled hi the art. Like numbers refer to like elements throughout.

The present invention is an adjustable height, standing desk 10 for use on top of a conventional desk or other elevated surface. The standing desk of the present invention 10 allows office workers to work while standing during the work day and thereby gain the advantages of breaks from continual sitting for hours at a time. The standing desk 10 is readily portable between locations and can be taken from job to job by a worker.

With reference to FIGS. 1-4, in one embodiment, the “power” version of the standing desk, the desk 10 includes a base frame assembly 12, an intermediate frame assembly 14 and an upper frame assembly 16. The upper frame assembly 16 will generally be equipped with a top support surface 18 which is designed to support typical desktop materials, i.e. books, writing pads, keyboards, display monitors and like materials. The base frame assembly 12 and intermediate frame assembly 14 may optionally be equipped with a base cover or support surface 20 and an intermediate cover or support surface 22. The base and intermediate support surfaces, 20 and 22, may also be used to support desktop materials when the adjustable height, standing desk 10 is in a raised position. The standing desk 10 may optionally be equipped with a slide out keyboard tray 40.

The base frame assembly 12, intermediate frame assembly 14 and upper frame assembly 16 are generally planar assemblies composed of rails in the form of channel-style extrusions. In the exemplary embodiment of FIGS. 1-4, the base, intermediate and upper frame assemblies are rectangular. The upper frame assembly comprises short side (left and right) rails 24 and long side rails 26, the intermediate frame assembly comprises short side (left and right) rails 28 and long side rails 30, and the base frame assembly comprises short side (left and right) rails 32 and long side rails 34. The base frame assembly 12 rests on top of and is joined to a base 36, which comprises a case assembly for housing a motor drive assembly 38 (see FIGS. 2-4).

The base frame assembly 12, intermediate frame assembly 14 and upper frame assembly 16 are interconnected by scissor lift linkage assemblies 42A and 42B which raise and lower the intermediate frame assembly 14 and upper frame assembly 16 in relation to the base frame assembly 12 and maintain the assemblies in a generally parallel relationship relative to each other as the top support surface 18 of the standing desk 10 moves between raised and lowered positions.

In the exemplary embodiment of the standing desk 10 depicted in the FIGS. 1-4, the opposing (left and right) scissor lift linkage assemblies 42A and 42B are installed in the opposing (left and right) short side rails of each frame assembly. The scissor lift linkage assemblies 42A and 42B on the opposing sides are essentially the same, therefore only one linkage assembly need be described in detail.

With reference principally to FIG. 4, the scissor lift linkage assembly 42A of the standing desk 10 of the present invention will be described in detail. The scissor lift linkage assembly 42A, comprises a lower link assembly 44 and an upper link assembly 46. The lower link assembly comprises links 48 and 50, where the lower links 48 and 50 are interconnected at mid-length to form a pivot connection 52. The upper link assembly comprises links 54 and 56, where the upper links 54 and 56 are interconnected at mid-length to form a pivot connection 58. Each of the links has an upper and a lower link end. Lower link 48 has a lower link end 60 and an upper link end 62. Lower link 50 has a lower link end 64 and an upper link end 66. Upper link 54 has a lower link end 68 and an upper link end 70. Upper link 54 has lower link end 72 and an upper link 74.

Link Connections to the Base Frame Assembly

The lower link end 60 of the lower link 48 is pivotally connected to the rail 32 of the base frame assembly 12 to form base frame fixed pivot connection 78 Base frame fixed pivot connection 78 is a fixed pivot, i.e. the lower link end 64 is pinned to the rail 32 such that it can rotate, but may not translate in any direction. The lower link end 64 of the lower link 50 is pivotally connected to a roller 98 via an axle 100 (see FIG. 12). This connection between lower link end 64 and roller 98 is referred to as base frame movable pivot connection 76, i.e. the roller equipped lower link end 64 is free to move or slide horizontally within the rail 32 of the base frame assembly 12.

Link Connections to the Intermediate Frame Assembly

Lower link end 72 of upper link 54 is pivotally connected to upper link end 66 of lower link 50 to form intermediate frame fixed pivot connection 82, i.e. intermediate frame fixed pivot connection 82 is pinned to the rail 28 of the intermediate frame assembly 14. Thus, the link ends 72 and 66 can rotate at the intermediate frame fixed pivot connection 82, but cannot translate in any direction. Lower link end 68 of upper link 56 is pivotally connected to upper link end 62 of tower link 48. Both link ends 68 and 62 are pivotally connected to roller 102 via a common axle 104. (See FIG. 13.) This connection of link ends 68 and 62 to roller 102 is referred to as intermediate frame movable pivot connection 80, i.e. the roller equipped lower link ends 68 and 62 are free to move or slide horizontally within the rail 28 of the intermediate frame assembly 14.

Link Connections to the Upper Frame Assembly

The upper link end 70 of the upper link 56 is pivotally connected to the rail 24 of the upper frame assembly 16 to form upper frame fixed pivot connection 86. Upper frame fixed pivot connection 86 is a fixed pivot, i.e. the upper link end 70 is pinned to the rail 24 such that it can rotate, but may not translate in any direction. The upper link end 74 of the upper link 54 is pivotally connected to a roller 106 via an axle 108. (See FIG. 14.) This connection of link end 74 of upper link 54 is referred to as upper frame movable pivot connection 84, i.e. the roller equipped upper link end 74 is free to move or slide horizontally within the rail 24 of the upper frame assembly 16.

The provision of the rollers 98, 102 and 106 at the movable pivot connections 76, 80 and 84 significantly reduces the frictional surface contact between the link ends 64, 68 and 74 and the rails 32, 28 and 26 of the base, intermediate and upper frame assemblies.

It should be noted that the fixed pivot connections 78, 82 and 86 are all vertically aligned, i.e. the base frame fixed pivot connection 78, the intermediate frame fixed pivot connection 82 and the upper frame fixed pivot connection 86 are vertically aligned with each other. The horizontal position of the base, intermediate and upper frame fixed pivot connections 78, 82 and 86 does not change as the scissor linkages 42A and 42B are used to raise and lower the top support surface 18 of the standing desk 10. The base, intermediate and upper frame movable pivot connections 76, 80 and 84 are also vertically aligned with each other, i.e. the base frame movable pivot connection 76, the intermediate frame movable pivot connection 80 and the upper frame movable pivot connection 84 are all vertically aligned with each other. The movable pivot connections (76, 80, 84) however, move both horizontally (within the rails 32, 28 34) of the base, intermediate and upper frame assemblies (12, 14, 16) and vertically as the scissor linkages are used to raise and lower the top support surface 18. Throughout the raising and lowering process, the base, intermediate and upper frame movable pivot connections remain vertically aligned.

With reference to FIG. 24 and particularly FIGS. 3-4, in this embodiment of the standing desk of the present invention 10, the scissor lift linkage assemblies 42A and 42B are electrically operated. The drive mechanism assembly 38 for raising and lowering the linkage assemblies 42A and 42B includes right ball screw assembly 110B and opposing left ball screw assembly 110A. Each of the ball screw assemblies 110A and 110B is disposed inside the base assembly 36 and adjacent and parallel to one of the short side rails 32 of the base frame assembly 12. One of the ball screw assemblies is motor driven by an electric drive motor 114. In the exemplary embodiment, the electric drive motor 114 is connected to right ball screw assembly 110B. The left and right ball screw assemblies 110A and 110E are synchronized via a chain and gear connection 116 between the two ball screw assemblies, where the chain and gear connection 116 comprises a chain 116A and a gear 1168 located on each of the ball screw assemblies 110A and 110B. Given that the ball screw assemblies 110A and 110B are synchronized via the chain and gear connection 116, both scissor linkages assemblies 42A and 42B will rise and fall in tandem in response to operation of the electric drive motor 114. Although shown and described as being connected to right ball screw assembly 110A, the electric drive motor 114 may optionally be connected to the left ball screw assembly 110B.

As is known in the art, ball screw assemblies comprise a screw portion and a nut portion where the nut 118 moves linearly along the length of the rotating screw 130. (See FIG. 4). Typically clockwise rotation drives the nut forward along the length of the screw and counter-clockwise rotation drives the nut backwards. In the standing desk of the present invention 10, the nut 118 of each ball screw assembly (110A, 110B) is connected to one of the opposing scissor lift linkage assemblies (42A, 42B) via a drive arm 120. (See FIG. 4.)

The scissor lift linkage assemblies 42A and 42B and the ball screw assemblies 110A and 110B are essentially identical and the connections between the ball screw assemblies and the scissor lift linkages are likewise essentially identical. Therefore, the connection between only one ball screw assembly and one scissor lift linkage need be described in detail. For purposes of illustration, the connection between ball screw assembly 110A and scissor lift linkage assembly 42A will be described.

Referring to scissor lift linkage assembly 42A and FIGS. 3-4, the drive arm 120 is connected to lower link 50 of the lower link pair 44. The lower end 64 of lower link 50 is connected to the roller 98 and forms the base frame movable pivot connection 76. The drive arm 120 is rigidly fixed to the lower link 50, but is pivotally connected to the ball screw assembly nut 118. The ball screw assembly 42A has a fixed end 126 and a free end 128. The fixed end 126 is pivotally mounted to the base frame assembly 36 via a pin 122 to form pivot connection 124. At pivot connection 124, the ball screw assembly 42A is free to rotate about the pin 122, but may not translate in any direction. As a consequence of the fixed end 124 of the ball screw assembly 42A being pinned, the free end 128 is free to rotate upwardly and downwardly along an arc in response to actuation of the screw.

Thus, as the screw 130 of the ball screw assembly 110A rotates clockwise, the nut 118 moves forwardly along the screw 130 causing the ball screw assembly 110A to rotate upwardly as the scissor lift linkage assembly 42A raises the top support surface 18 of the standing desk 10 upwardly. Likewise, when the screw 130 of the ball screw assembly 42A is rotated counterclockwise, the nut 118 moves backwardly along the screw 130 causing the ball screw assembly 110A to rotate downwardly as the scissor lift linkage assembly 42A lowers the top surface 18. As referenced above, both of the ball screw assemblies 42A and 42B move in tandem because the assemblies are synchronized via the chain and gear connection 116.

Ball screw assembles suitable for use with the present invention are commercially available from Shangyu Appliance Corporation. Suitable electric motors, control electronics, and synchronizing chains and gears are commercially available and known to those of skill in the art. In the exemplary embodiment of the present invention depicted in FIGS. 1-4, a contact switch (not shown) is provided for controlling operation of the electric drive motor and thus, the raising and lowering the standing desk.

With reference to FIGS. 2-3, the standing desk 10 of FIGS. 1-4 is also equipped with cross braces 132 and 134. Brace 132 interconnects the upper ends 66 of the lower linkage arms 50 of the opposing linkage assemblies 42A and 42B. Similarly, brace 134 interconnects the upper ends 70 of the upper linkage arms 56 of the opposing linkage assemblies. Cross braces 132 and 134 thereby provide added rigidity and strength to the structure of the standing desk 10.

With reference to FIGS. 6-10, an alternative embodiment of the standing desk of the present invention, referred to as the “manual version,” is presented. The manual version 136 of the standing desk is similar in design to that of the power version of the desk 10, in that both versions use base, intermediate and upper frame assemblies 12, 14 and 16 and scissor lift linkage assemblies 42A and 42B of similar design with no significant variation in design principles or function. Therefore, these elements of the manual version of the standing desk 136 will be numbered accordingly in FIGS. 6-10 and there descriptions need not be repeated.

The manual version of the standing desk 136 differs from the power version of the standing desk 10 in that a motor drive assembly is not used to actuate the scissor lift linkage assemblies 42A and 42B. Rather, the manual version of the standing desk 136 is equipped with biasing springs 138 which connect at one end to a cross brace 140. The cross brace 140 is rigidly connected at each end to the upper ends 70 of the upper links 56 of the linkage assemblies 42A and 42B. At their opposite ends, the biasing springs 138 are connected to the long side frame rail 26 disposed adjacent to the upper frame fixed pivot connections 86. Via this connection, i.e. to the cross brace 140 and to the long side frame rail 26 adjacent the fixed pivot connections 86, the biasing springs 138 bias the scissor lift linkage assemblies 42A and 42B such that the standing desk 136 tends to rise to a fully raised position, unless otherwise restrained. The biased linkages 42A and 42B are biased to rise to the fully raised position at linkage extensions of about ¼ height or greater.

The maximum height of the standing desk 136 is controlled by limiting the maximum extension of the scissor lift linkage assemblies 42A and 42B via an abutment 144 (see FIG. 9) included on upper short side frame rails 24 of the manual version of the standing desk 136.

If less than the full height of the manual version of the standing desk 136 is desired, a user exerts manual compressive force on the top support surface 18 sufficient to overcome the force exerted by the biasing springs to collapse the scissor lift linkages 42A and 42B and thereby lower the desk 136. A height adjustment linkage assembly 142 is provided for locking the desk height in a number of predetermined positions.

A feature of the manual version of the standing desk 136 is that the biasing springs 138 are located such that they have an “over-center” position which causes the springs 138 to bias the standing desk 136 to a closed position at scissor lift linkage extensions (heights) below about ¼ of maximum extension or height. Therefore, to fully collapse the manual version of the standing desk 136 a user need only exert compressive force on the top support surface 18 until the desk 136 is near fully collapsed, i.e. is compressed to about ¼ height or less, and the biasing springs 138 will hold the scissor lift linkage assemblies 42A and 42B in the closed position.

As referenced above, height adjustment of the manual version of the standing desk 136 is controlled by the height adjustment linkage assembly 142. With reference principally to FIGS. 8-10, height adjustment linkage assembly 142 comprises left and right spring loaded retractable pins 146A and 146B, a pivot plate 148, right and left cables 154 and 152, a release handle 150, a release cable 158 and a plurality of pin engagement holes 154 (see FIG. 9). The retractable pins 146 are mounted to the upper links 54 of the linkage assemblies 42A and 42B and serve a dual function as both locking pins and as the axles 108 for the rollers 106 of the upper frame movable pivot connections 84. The retractable pins 146A and 1463 are spring loaded such that the pins are biased to a fully extended position in their at rest state. Left and right cables 154 and 152 interconnect the left and right retractable pins 146A and 146B with the pivot plate 148. The pivot plate in turn is connected to the release handle 150 via the release cable 158. The pivot plate 148 is configured such that the actuation of the release handle causes the right and left retractable pins to retract inwardly. Upon release of the handle the biasing springs within the pins bias the pins to their fully extended position.

Height control is accomplished by equipping the short side frame rails 24 with a series of height adjustment holes 154. The retractable pins 146A and 146B upon engaging pairs of horizontally aligned holes 154 in the left and right side frame rails 24, lock the desk 136 in the height position predetermined by the hole placement in the frame rails. The height adjustment holes 154 may be placed directly in the frame rails 24 or, in the exemplary embodiment, for the purposes of improved cosmetics an inner channel 160 (best shown in FIG. 10) may be fixed within the channel of the frame rail 24. The use of the inner channel 160 allows for the height adjustment holes 154 and height adjustment pins 146A and 146B to be hidden from view and therein provides for an improved cosmetic experience.

Optionally, either version of the standing desk of the present invention may be equipped with a keyboard tray. With reference to FIGS. 6 and 11, the manual version of the desk 136 features a clip-on keyboard tray 162 comprising keyboard platform 164 and keyboard engagement prongs 166 which engage slots 168 (see FIG. 6) in the support surface 20. The clip-on keyboard tray 162 may optionally be equipped with a clip-on mouse pad 184 which engages with a slot 186 formed into the keyboard tray 162. The keyboard tray 162 may include the slot 186 on both right and left hand sides of the tray to allow for easy installation of the mouse pad 184 on either side of the tray as may be desired by a user.

With reference to FIGS. 1 and 5, in the exemplary embodiment, the power version of the standing desk 10 features a pull-out keyboard tray 40. The pull-out keyboard tray 40 includes a tray portion 170, a base portion 172 and two pairs of parallel swing arms 174 and 176. (The left side arms are shown in FIG. 5.) The swing arms 174 and 176 allow the tray portion to swing between a closed and a raised position. Biasing springs 178 interconnecting the base portion 172 and the tray portion 170 are included to bias the tray portion 170 upwardly when a user desires to raise the tray. The keyboard tray 40 is also equipped with slide rails 180 which engage with mating rails 182 in the base 36, (see FIG. 2), which allow the tray 40 to be slid in and out of the base 36.

The standing desk of the present invention, both manual and power versions, may be made from a variety of materials. Metallic materials such as steel and aluminum are well suited for the frame and linkage members. Structural plastics and like materials may also be suitable. The support surfaces (desktop surfaces) may be made of metallic materials or plastic materials. Wood desktops may also be suitable.

The foregoing detailed description and appended drawings are intended as a description of the presently preferred embodiment of the invention and are not intended to represent the only forms in which the present invention may be constructed and/or utilized. Those skilled in the art will understand that modifications and alternative embodiments of the present invention which do not depart from the spirit and scope of the foregoing specification and drawings, and of the claims appended below are possible and practical. It is intended that the claims cover all such modifications and alternative embodiments. 

1. A height adjustable table, comprising: a base frame, an intermediate frame and an upper frame, wherein the base, intermediate and upper frames are parallel to each other and configured in a vertically spaced and aligned relationship; wherein the base, intermediate and upper frames each include a frame member and wherein the frame member of the base, intermediate and upper frames are parallel to each other and vertically aligned; a linkage assembly for maintaining the base, intermediate and upper frames in a generally parallel relationship relative to each other as the table moves between raised and lowered positions; wherein the linkage assembly is pivotally connected at a first location and slidably connected at a second location to the frame member of each of the base, intermediate and upper frames; and a drive assembly for raising and lowering the table, the drive assembly connected to the linkage assembly.
 2. The height adjustable table of claim 1, wherein the linkage assembly is: a scissor linkage comprising of a pair of lower links having lower and upper ends and a pair of upper links having lower and upper ends, the lower links being pivotally connected at about their mid-length, the upper links being pivotally connected at about their mid-length; wherein one of the lower ends of the lower links is pivotally connected to the frame member of the base frame, and the other lower end of the lower links is slidably connected to the frame member of the base frame; wherein one of the upper ends of the lower links is pivotally connected to one of the lower ends of the upper links and to the frame member of the intermediate frame, and the other upper end of the lower links is pivotally connected to the other lower end of the upper links and slidably connected to the frame member of the intermediate frame; wherein one of the upper ends of the upper links is pivotally connected to the frame member of the upper frame, and the other of the upper ends of the upper links is slidably connected to the frame member of the upper frame; and wherein the upper and lower link pivot connections on the frame member of the base, intermediate and upper frames are vertically aligned and the upper and lower link slideable connections on the frame member of the base, intermediate and upper frames are vertically aligned.
 3. The height adjustable table of claim 1, wherein the drive assembly for raising and lowering the table comprises: a ball screw assembly, the ball screw assembly being disposed adjacent and generally parallel to the linkage assembly; a linkage arm, wherein the linkage arm interconnects the ball screw assembly and adjacent linkage assembly; and a drive motor connected to one of the ball screw assemblies.
 4. The height adjustable table of claim 3, wherein the drive motor is an electric motor.
 5. The height adjustable table of claim 3, wherein for the ball screw assembly and adjacent linkage assembly, the linkage arm is rigidly connected to the lower link of the linkage assembly slidably connected to the frame member of the base frame and is pivotally connected to a nut of the ball screw assembly.
 6. The height adjustable table of claim 5, wherein the ball screw assembly is pivotally connected at one end and free to rotate in an arc at the other end in a plane generally parallel to the adjacent connected linkage assembly.
 7. The height adjustable table of claim 1, wherein the drive assembly is enclosed within a base connected to the base frame.
 8. The height adjustable table of claim 1, wherein the slidable connections between the lower and upper links and the frame member of the base, intermediate and upper frames include rollers fixed to the links which slide upon the frame members.
 9. The height adjustable table of claim 1, wherein the upper frame includes a top support surface or table top connected to the frame.
 10. The height adjustable table of claim 1, wherein the intermediate frame includes a support surface connected to the frame.
 11. The height adjustable table of claim 1, wherein the base frame includes a top support surface connected to the frame.
 12. The height adjustable table of claim 7, further including a pull-out keyboard tray in the base.
 13. A height adjustable table, comprising: a base frame, an intermediate frame and an upper frame, wherein the base, intermediate and upper frames are parallel to each other and configured in a vertically spaced and aligned relationship; wherein the base, intermediate and upper frames each include a frame member and wherein the frame member of the base, intermediate and upper frames are parallel to each other and vertically aligned; a linkage assembly for maintaining the base, intermediate and upper frames in a generally parallel relationship relative to each other as the table moves between raised and lowered positions; wherein the linkage assembly is pivotally connected at a first location and slidably connected at a second location to the frame member of each of the base, intermediate and upper frames; means for biasing the height-adjustable table in a normally raised position; and means for adjusting the height of the height-adjustable table.
 14. The height-adjustable table of claim 13, wherein the means for biasing the height-adjustable table in a normally raised position comprises biasing springs interconnecting the upper ends of the upper links of the linkage assembly.
 15. The height-adjustable table of claim 13, wherein the means for adjusting the height of the table includes a pin mounted at the upper end of the upper link slidably connected to the frame member of the upper frame, the pin configured to selectively engage the frame member at predetermined height-adjustment locations.
 16. A height adjustable table, comprising: a base frame, an intermediate frame and an upper frame, wherein the base, intermediate and upper frames are parallel to each other and configured in a vertically spaced and aligned relationship; wherein the base, intermediate and upper frames each include mutually opposed side members and wherein the side members of the base, intermediate and upper frames are parallel to each other and vertically aligned; two linkage assemblies for maintaining the base, intermediate and upper frames in a generally parallel relationship relative to each other as the table moves between raised and lowered positions; wherein one of the two linkage assemblies is pivotally connected at a first location and slidably connected at a second location to a side member of each of the base, intermediate and upper frames and the other linkage assembly is pivotally connected at a first location and slidably connected at a second location to an opposing side member of each of the base, intermediate and upper frames; wherein each linkage assembly is a scissor linkage comprising a pair of lower links having lower and upper ends and a pair of upper links having lower and upper ends, the lower links being pivotally connected at about their mid-length, the upper links being pivotally connected at about their mid-length; wherein one of the lower ends of the lower links is pivotally connected to the side member of the base frame, and the other lower end of the lower links is slidably connected to the side member of the base frame; wherein one of the upper ends of the lower links is pivotally connected to one of the lower ends of the upper links and to the side member of the intermediate frame, and the other upper end of the lower links is pivotally connected to the other lower end of the upper links and slidably connected to the side member of the intermediate frame; wherein one of the upper ends of the upper links is pivotally connected to the side member of the upper frame, and the other of the upper ends of the upper links is slidably connected to the side member of the upper frame; wherein for each linkage assembly, the upper and lower link pivot connections on the side members of the base, intermediate and upper frames are vertically aligned and the upper and lower link slideable connections on the side members of the base, intermediate and upper frames are vertically aligned; and a drive assembly for raising and lowering the table, the drive assembly connected to each of the linkage assemblies.
 17. The height adjustable table of claim 16, wherein the drive assembly for raising and lowering the table comprises: two ball screw assemblies, one of the ball screw assemblies being disposed adjacent and generally parallel to one of the linkage assemblies, the other ball screw assembly being disposed adjacent and generally parallel to the other linkage assembly; two linkage arms, wherein one linkage arm interconnects one of the ball screw assemblies and adjacent linkage assemblies and the other linkage arm connects the other ball screw assembly and adjacent linkage assembly; wherein for each ball screw assembly and adjacent linkage assembly, the linkage arm is rigidly connected to the lower link of linkage assembly slidably connected to the side member of the base frame and is pivotally connected to a nut of the ball screw assembly; a means for synchronizing the two ball screw assemblies; and a drive motor connected to one of the ball screw assemblies.
 18. The height adjustable table of claim 17, wherein the means for synchronizing the two ball screw assemblies is a chain and gear connection.
 19. The height adjustable table of claim 5, wherein each ball screw assembly is pivotally connected at one end and free to rotate in an arc at the other end in a plane generally parallel to the adjacent connected linkage assembly.
 20. The height adjustable table of claim 16, wherein the drive assembly is enclosed within a base connected to the base frame. 